The fill level should be read with the plug resting on the hole, not screwed in.
A number of these Chinese tractors seem topee hydraulic fluid when going up steep grades, due to the location of the breather on top of the lift box. Some guys just cobble together an extension of the breather by running a tube from it up the side of the ROPS and this solves the problem.
Almost any of the dealers who respond here, such as Affordable Tractor Sales, Blue Chip, etc, can supply you with parts if needed and will happily ship to OZ.